1. Field of the Invention
The present invention relates to a magnetoresistive (MR) element utilizing a magnetoresistive (MR) film such as a so-called spin valve film, for example. In particular, the invention relates to a current-perpendicular-to-the-plane (CPP) structure MR element allowing a sensing current to have a component perpendicular to the surface of a substratum receiving a MR film.
2. Description of the Prior Art
A conventional CPP structure MR element often includes a so-called spin valve film. The spin valve film includes a free magnetic layer and a pinned magnetic layer. A non-magnetic intermediate layer is interposed between the free and pinned magnetic layers. The non-magnetic intermediate layer serves to isolate the magnetization of the free magnetic layer from the pinned magnetic layer. The magnetization is allowed to rotate in the free magnetic layer in response to changes in the polarization of the magnetic field acting on the free magnetic layer. The rotation of the magnetization causes the electric resistance of the spin valve film to vary. Variation is induced in the voltage of the sensing current flowing through the spin valve film.
In general, the spin valve film is made of electrically-conductive materials. The sensing current is allowed to flow in the spin valve film over the entire cross-section. Unless the spin valve film is further diminished, it is impossible to reduce the cross-section of the path for the sensing current. If the path for the sensing current is thinned, a larger variation in voltage can be detected in the sensing current. The output of the CPP structure MR element can be enhanced.